Postcyclic behavior of low-plasticity silt with limited excess pore pressures

• The undrained shear strength increases significantly when Ru>0.70.
• The yield shear strength and initial stiffness were reduced with an increase in Ru.
• Large εv due to reconsolidation developed at less Ru for silt than for sand.
• The postcyclic undrained shear strength falls within the range reported by others.

This paper investigates the postcyclic behavior of low-plasticity silt with excess pore pressure ratio (Ru) less than 1. The testing specimens were prepared from Mississippi River Valley (MRV) silt. Full and no reconsolidation were allowed after specimens were subjected to various excess pore pressure ratios due to cyclic loading in a cyclic triaxial cell, and then monotonic shear tests were conducted. The effect of the Ru on shear strength and stiffness at small and large deformation was investigated. It was found that a Ru greater than 0.70 is a prerequisite of large increase in volumetric strain and undrained shear strength for specimens with full reconsolidation. In contrast, a significant decrease in yield shear strength and initial stiffness was noted for specimens without reconsolidation. In comparison to published data for sands, the silt experienced significant volumetric strain due to reconsolidation at lower Ru, indicating that the specimen fabric was modified or strained at lower Ru.